There's lots of both, and you can always find one rule to contradict another.

For making it taste better, brewing good tea is kind of like baking; there is some precision chemistry involved, so following someone else's recipe exactly is a good idea unless you have a fair bit of experience, enough to know where there is wiggle room. For example, as with baking, the wrong temperature can get you an unholy mess.

I used to be doubtful that the material of a teapot could make the difference in the taste of the tea that some people said it would, until I confirmed it by experiment. Then I realized that I'd known from experience since childhood that the material of a baking pan could make a big difference in a cake, so I don't know what my problem was believing teapot material is just as important.

I feel like I'm pimping Teamasters everywhere today, but that's the blog that got me off and rolling on making good tea.